Display color affects motion sickness symptoms in an optokinetic drum

BACKGROUND: Many stationary participants who view the patterned interior of a rotating cylinder (optokinetic drum) experience motion sickness (MS) symptoms. Most drum interiors have consisted of black and white patterns. An experiment was conducted to investigate the effects of chromaticity on MS onset and severity. METHODS: There were 12 individuals who participated in the experiment (4 men, 8 women, mean age = 25). Keeping rotation speed constant (5 RPM), the color of vertical stripes in an optokinetic drum was manipulated. There were three conditions used: 1) alternating black and white stripes; 2) gray stripes having different luminance values; and 3) chromatic stripes (white, red, yellow, black, green, and blue) that approximately matched the luminance values of the stripes in the gray condition. Every 2 min, eight motion sickness symptoms were assessed (for up to 16 min) using a subjective scale (0 = none, 1 = slight, 2 = moderate, 3 = severe). RESULTS: Overall, MS onset was fastest, and symptoms the most severe, in the chromatic condition. The two major MS symptoms that were significantly affected were headache and dizziness. CONCLUSIONS: Chromaticity may affect how much an observer's visual environment appears to be stationary, perhaps because chromaticity is such a common feature of the stationary environment in which our visual system evolved. In an optokinetic drum, the addition of chromaticity may increase the disparity between visual and vestibular inputs, a factor thought by many to contribute to MS onset and severity.     

Flow dynamics of the St Jude Medical Symmetry aortic connector vein graft anastomosis do not contribute to the risk of acute thrombosis

BACKGROUND: The efficacy of the St Jude Medical Symmetry aortic connector (St Jude Medical, Inc, St Paul, Minn) for coronary artery bypass is currently debated. Potential drawbacks are the biocompatibility of the endoluminal device, the need for graft manipulation during the procedure, and the 90 degrees offset of the vein graft from the ascending aorta, which may induce graft kinking and abnormal fluid dynamics. In this article, a computational approach was designed to investigate the fluid dynamics pattern at the proximal graft. METHODS: Four models of hand-sewn anastomoses and two models of automated anastomoses were constructed; a finite volume technique was used to simulate realistic graft fluid dynamics, including aortic compliance and proper aortic and graft flow rates. The anastomosis geometry performance was analyzed by calculating time-averaged wall shear stress and the oscillating shear index at the toe and heel regions of the proximal graft. RESULTS: Time-averaged wall shear stress was significantly lower in the hand-sewn anastomosis models than in the two models that simulated the use of the aortic connector (0.38 +/- 0.07 Pa vs 1.32 +/- 0.4 Pa). Higher oscillating shear index values were calculated in the hand-sewn anastomosis models (0.15 +/- 0.02 Pa vs 0.06 +/- 0.02 Pa). CONCLUSIONS: Automated anastomosis geometry is associated with less critical fluid dynamics than with conventional hand-sewn anastomosis: the shape of the proximal graft induces more physiological wall shear stresses and less oscillating flow, suggesting a lower risk of atherosclerotic plaque and intimal hyperplasia as compared with conventional anastomosis geometry. Therefore, the reported early thrombosis and late failure of the St Jude Medical aortic connector anastomoses are not related to unfavorable fluid dynamics.     

An open-label randomized trial of the safety and efficacy of sirolimus vs. azathioprine in living related renal allograft recipients receiving cyclosporine and prednisone combination

BACKGROUND: The ability of sirolimus (SRL), in combination with reduced exposure of cyclosporine, was investigated to prevent acute rejection and associated side effects. METHODS: Between June 1999 and February 2000, 70 recipients of primary one-haplotype living-related donor renal allografts were randomized to receive SRL (2 mg/d) or azathioprine (AZA) (2 mg/kg/d) combined with cyclosporine and prednisone. The primary end-point was a composite of first occurrence of biopsy-confirmed acute rejection, graft loss, or death during the first 3 months after transplantation. RESULTS: From week 4 to month 12, SRL patients received lower cyclosporine (week 4: 364 mg/d vs. 455 mg/d, p = 0.004; month 12: 195 mg/d vs. 255 mg/d, p = 0.038) doses and showed lower cyclosporine concentrations (week 4: 247 ng/mL vs. 309 ng/mL, p = 0.04; month 12: 143 ng/mL vs. 188 ng/mL, p = 0.045). Compared with AZA, SRL patients showed reduced 3-month primary end point (0% vs. 17.1%, p = 0.025), and reduced incidence of biopsy-confirmed acute rejection at 3 months (0% vs. 14.3%, p = 0.01) but not at 12 months (11.4% vs. 14.3%, NS). Mean creatinine at 12 months were not different (1.8 +/- 0.6 vs. 1.6 +/- 0.6, p = 0.23). Hyperlipidemia was the only adverse event more frequent among SRL patients (49% vs. 17%, p = 0.01). There were no differences in infections and no malignancies in both groups. CONCLUSIONS: The combination of 2 mg fixed doses of SRL, reduced cyclosporine exposure and prednisone was associated with a low incidence of acute rejection and did not result in significantly impaired graft function compared with patients receiving AZA, standard doses of cyclosporine and prednisone.     

Mesenteric vein thrombosis after surgery and radiotherapy for pancreatic carcinoma. A case report

A case is reported of a 54-year-old female patient undergoing the resection of a pancreatic carcinoma with intraoperative radiation therapy (10 Gy) on the tumor bed and subsequent external beam radiotherapy (50 Gy). After surgery the patient presented chronic diarrhea resistant to oral pancreatic enzymes. Twenty-five months postoperatively, mesenteric vein thrombosis was diagnosed after an episode of melena and was treated with conservative therapy. At five-year follow-up the patient had no evidence of neoplastic disease and bowel movements had increased. On imaging examinations, the presence of venous collaterals and cavernous appearance of the portal trunk were documented.     

Skin reaction in antiviral therapy for chronic hepatitis C: a role for polyethylene glycol interferon?

In the past decade, different modalities of antiviral therapy have been adopted aimed at eradicating hepatitis C virus infection. Initially, interferon was used in monotherapy, then interferon combined with ribavirin and amantadine. Recently, interferon has been conjugated with polyethylene glycol to allow optimization of its pharmacokinetic properties and to improve its antiviral activity. This study focused on the characteristics of the skin reactions that we observed in 27 patients with na?ve hepatitis C who received polyethylene glycol interferon-ribavirin-amantadine or polyethylene glycol interferon-ribavirin and in 10 previous non-responders to interferon monotherapy who were retreated with triple therapy. In 9 patients (7 on triple therapy) dermatitis-like lesions were observed, and in 5 the severity of the lesions necessitated withdrawal from therapy.     

A collection of 33 novel human mtDNA homoplasmic variants

Mitochondria are involved in cellular energy production via oxidative phosphorylation and this function may be damaged by any mutation in mitochondrial DNA (mtDNA). To identify novel mtDNA mutations, we have developed a program to systematically screen the entire mitochondrial genome in a large number of individuals with clinical and/or morphological features of mitochondrial dysfunction, but still no genetic diagnosis. The sequence-data were obtained with an automated rapid system, which gave us a series of information: in the eleven mitochondrial genomes analyzed we observed the presence of 33 differences from the revised Cambridge Reference Sequence (Andrews et al., 1999), but they were all homoplasmic in the patients' tissues analyzed (skeletal muscle and blood), suggesting that they are unlikely to be primarily pathogenic though they may be co-responsible in the determination of the disease. This work can therefore help complete the already ample mtDNA polymorphism existent database.     

A simplified technique for antegrade selective cerebral perfusion

Various methods of cerebral protection have been used during aortic arch surgery. We reviewed our experience with a modified technique for selective cerebral perfusion (SCP) administration during surgery on the thoracic aorta from October 1999. Conventionally, this technique requires an additional roller pump on the cardiopulmonary bypass (CPB) console. In order to simplify the extracorporeal circuit (ECC), the paediatric double-roller pump used for the administration of cardioplegia was utilized by adding a 'Y-connection' on the blood line of the cardioplegia circuit, upstream of the cardioplegia reservoir, to provide SCP blood flow. SCP administration with a Y-connection is both easy and fast to set up on the ECC circuit and does not create additional difficulties to the surgeon. It simplifies SCP delivery by allowing the perfusionist to use a standard ECC system set-up.     

Endoscopic endonasal approach to the pterygopalatine fossa: anatomic study

OBJECTIVE: The pterygopalatine fossa is a relatively small anatomic region. Because of its rich vasculonervous contents and its connections with several intracranial and extracranial compartments, it is of particular surgical interest. Because of its deep localization and despite its small size, however, it can require extensive anatomic approaches, especially for invasive cranial base lesions. We performed a cadaveric study through a minimally invasive endoscopic endonasal approach to the pterygopalatine fossa. METHODS: We studied 16 pterygopalatine fossae in eight adult cadaveric heads in which the arteries and veins were injected with latex. For visualization, we used rod-lens endoscopes, 4 mm in diameter and 18 cm in length, with 0-, 30-, 45-, and 70-degree lenses. An endonasal middle meatal transpalatine approach, an endonasal middle meatal transantral approach, and an endonasal inferior turbinectomy transantral approach were used. RESULTS: The middle meatal transpalatine approach allows for medial exposure of the pterygopalatine fossa contents, the middle meatal transantral approach allows a lateral view, and the inferior turbinectomy transantral approach allows the widest view and room for surgical maneuvering in the medial and lateral compartments of the pterygopalatine fossa and the infratemporal fossa. CONCLUSION: Our anatomic study shows that this approach can be considered a valid minimally invasive option to approach pterygopalatine fossa lesions.